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شركة الطلاب الخريجين بالسودان

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  1. [1]
    mtztaj
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    تاريخ التسجيل: Jul 2006
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    شركة الطلاب الخريجين بالسودان

    أرجو الاهتمام بالاتي :
    - معلومات عن خام المنجنيز
    - معلومات ومواقع شبكية عن طرق فتح مناجم الخام أعلاه
    - الطرق العملية للتفجير في المنجم المفتوح والمنجم تحت السطحي
    - الرجاء الارسال في اسرع وقت

    ملحوطة :
    - شركة الطلاب الخريجين في السوادن بصدد فتح مناجم منجنيز
    - سوف تقبل أفضل معلومات مرسلة وسيتم السحب حتى نهاية الشهر الحالي لذا سارعو
    - سيتم قبول أفضل شخص يرسل معلومات
    - يمنكم زيارة موقعنا عما قريب على شبكة المعلومات والانترنت

  2. [2]
    alshangiti
    alshangiti غير متواجد حالياً

    مشرف وإستشاري هندسة المناجم


    الصورة الرمزية alshangiti


    تاريخ التسجيل: Mar 2007
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    Manganese (pronounced /ˈmæŋgəniːz/) is a chemical element that has the symbol Mn and atomic number 25. It is found as the free element in nature (often in combination with iron), and in many minerals. The free element is a metal with important industrial metal alloy uses. Manganese ions are variously colored, and are used industrially as pigments and as oxidation chemicals. Manganese (II) ions function as cofactors for a number of enzymes; the element is thus a required trace mineral for all known living organisms.

    Industrially important compounds
    Methylcyclopentadienyl manganese tricarbonyl is used as an additive in unleaded gasoline to boost octane rating and reduce engine knocking. The manganese in this unusual organometalic compound is in the +1 oxidation state.
    The most stable oxidation state for manganese is +2, which has a pink to red color, and many manganese(II) compounds are known, such as manganese(II) sulfate (MnSO4) and manganese(II) chloride (MnCl2). This oxidation state is also seen in the mineral rhodochrosite, (manganese(II) carbonate). The +2 oxidation state is the state use in living organisms for essential functions; all of the other states are much more toxic.
    The +3 oxidation state is known, in compounds such as manganese(III) acetate, but these are quite powerful oxidizing agents.
    Manganese(IV) oxide (manganese dioxide, MnO2) is used as a reagent in organic chemistry for the oxidation of benzylic alcohols (i.e. adjacent to an aromatic ring). Manganese dioxide has been used since antiquity to oxidatively neutralize the greenish tinge in glass caused by trace amounts of iron contamination. MnO2 is also used in the manufacture of oxygen and chlorine, and in drying black paints. In some preparations it is a brown pigment that can be used to make paint and is a constituent of natural umber.
    Manganese(IV) oxide was used in the original type of dry cellbattery as an electron acceptor from zinc, and is the blackish material found when opening carbon-zinc type flashlight cells. The same material also functions in newer alkaline batteries (usually battery cells), which use the same basic reaction, but a different electrolyte mixture.
    Manganese phosphating is used as a treatment for rust and corrosion prevention on steel.
    Permanganate (+7 oxidation state) manganese compounds are purple, and can color glass an amethyst color. Potassium permanganate, sodium permanganate and barium permanganate are all potent oxidizers. Potassium permanganate, also called Condy's crystals, is a commonly used laboratory reagent because of its oxidizing properties and finds use as a topical medicine (for example, in the treatment of fish diseases). Solutions of potassium permanganate were among the first stains and fixatives to be used in the preparation of biological cells and tissues for electron microscopy
    Occurrence

    Manganese ore


    Manganese occurs principally as pyrolusite (MnO2), psilomelane (Ba(Mn2+)(Mn4+)8O16(OH)4), and to a lesser extent as rhodochrosite (MnCO3). Land-based resources are large but irregularly distributed; those of the United States are very low grade and have potentially high extraction costs. Over 80% of the known world manganese resources are found in South Africa and Ukraine. Other important manganese deposits are in China, Australia, Brazil, Gabon, India, and Mexico.

    Psilomelane (manganese ore)


    US Import Sources (1998-2001): Manganese ore: Gabon, 70%; South Africa, 10%; Australia, 9%; Mexico, 5%; and other, 6%. Ferromanganese: South Africa, 47%; France, 22%; Mexico, 8%; Australia, 8%; and other, 15%. Manganese contained in all manganese imports: South Africa, 31%; Gabon, 21%; Australia, 13%; Mexico, 8%; and other, 27%.
    Manganese is mined in Burkina Faso and Gabon.
    Vast quantities of manganese exist in manganese nodules on the ocean floor. Attempts to find economically viable methods of harvesting manganese nodules were abandoned in the 1970s

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  3. [3]
    alshangiti
    alshangiti غير متواجد حالياً

    مشرف وإستشاري هندسة المناجم


    الصورة الرمزية alshangiti


    تاريخ التسجيل: Mar 2007
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    Atomic number
    25
    Atomic mass
    54.9380 g.mol -1
    Electronegativity according to Pauling
    1.5
    Density
    7.43 g.cm-3 at 20°C
    Melting point
    1247 °C
    Boiling point
    2061 °C
    Vanderwaals radius
    0.126 nm
    Ionic radius
    0.08 nm (+2) ; 0.046 nm (+7)
    Isotopes
    7
    Electronic shell
    [ Ar ] 3d5 4s2
    Energy of first ionisation
    716 kJ.mol -1
    Energy of second ionisation
    1489 kJ.mol -1
    Standard potential
    - 1.05 V ( Mn2+/ Mn )
    Discovered
    Johann Gahn in 1774

    Manganese

    Manganese is a pinkinsh-gray, chemically active element. It is a hard metal and is very brittle. It is hardly melt, but easily oxidized. Manganese is reactive when pure, and as a powder it will burn in oxygen, it reacts with water (it rusts like iron) and dissolves in dilute acids.
    Applications
    Manganese is essential to iron and steel production. At present steel making accounts 85% to 90% of the total deman, most of the total demand. Manganese is a key component of low-cost stainless steel formulations and certain widely used alumimum alloys. Manganese dioxide is also used as a catalyst. Manganese is used to decolorize glass and make violet coloured glass. Potassium permanganate is a potent oxidizer and used as a disinfectant. Other compound that find application are Manganese oxide (MnO) and manganese carbonate (MnCO3): the first goes into fertilizers and ceramics, the second is the starting material for making other manganese compounds.
    Manganese in the environment
    Manganese is one of the most abundant metals in soils, where it occurs as oxides and hydroxides, and it cycles through its vaious oxidation states. Manganese occurs principally as pyrolusite (MnO2), and to a lesser extent as rhodochrosite (MnCO3). More than 25 million tonnes are mined every year, representing 5 million tons of the metal, and reserves are estimated to exeed 3 billion tonnes of the metal. The main mining areas for manganese ores are South Africa, Russia, Ukraine, Georgia, Gabon and Australia.
    Manganese is an essential element for all species. Some organisms, such as diatoms, molluscs and sponges, accumulate manganese. Fish can have up to 5 ppm and mammals up to 3 ppm in their tissue, although normally they have around 1 ppm.
    Health effects of manganese

    Manganese is a very common compound that can be found everywhere on earth. Manganese is one out of three toxic essential trace elements, which means that it is not only necessary for humans to survive, but it is also toxic when too high concentrations are present in a human body. When people do not live up to the recommended daily allowances their health will decrease. But when the uptake is too high health problems will also occur.

    The uptake of manganese by humans mainly takes place through food, such as spinach, tea and herbs. The foodstuffs that contain the highest concentrations are grains and rice, soya beans, eggs, nuts, olive oil, green beans and oysters. After absorption in the human body manganese will be transported through the blood to the liver, the kidneys, the pancreas and the endocrine glands.

    Manganese effects occur mainly in the respiratory tract and in the brains. Symptoms of manganese poisoning are hallucinations, forgetfulness and nerve damage. Manganese can also cause Parkinson, lung embolism and bronchitis. When men are exposed to manganese for a longer period of time they may become impotent.
    A syndrome that is caused by manganese has symptoms such as schizophrenia, dullness, weak muscles, headaches and insomnia.

    Because manganese is an essential element for human health shortages of manganese can also cause health effects. These are the following effects:

    - Fatness
    - Glucose intolerance
    - Blood clotting
    - Skin problems
    - Lowered cholesterol levels
    - Skeleton disorders
    - Birth defects
    - Changes of hair colour
    - Neurological symptoms
    Chronic Manganese poisoning may result from prolonged inhalation of dust and fume. The central nervous system is the chief site of damage from the disease, which may result in permanent disability. Symptoms include languor, sleepiness, weakness, emotional disturbances, spastic gait, recurring leg cramps, and paralysis. A high incidence of pneumonia and other upper respiratory infections has been found in workers exposed to dust or fume of Manganese compounds. Manganese compounds are experimental equivocal tumorigenic agents.
    Environmental effects of manganese

    Manganese compounds exist naturally in the environment as solids in the soils and small particles in the water. Manganese particles in air are present in dust particles. These usually settle to earth within a few days.
    Humans enhance manganese concentrations in the air by industrial activities and through burning fossil fuels. Manganese that derives from human sources can also enter surface water, groundwater and sewage water. Through the application of manganese pesticides, manganese will enter soils.

    For animals manganese is an essential component of over thirty-six enzymes that are used for the carbohydrate, protein and fat metabolism. With animals that eat too little manganese interference of normal growth, bone formation and reproduction will occur.

    For some animals the lethal dose is quite low, which means they have little chance to survive even smaller doses of manganese when these exceed the essential dose. Manganese substances can cause lung, liver and vascular disturbances, declines in blood pressure, failure in development of animal foetuses and brain damage.

    When manganese uptake takes place through the skin it can cause tremors and coordination failures. Finally, laboratory tests with test animals have shown that severe manganese poisoning should even be able to cause tumor development with animals.

    In plants manganese ions are transported to the leaves after uptake from soils. When too little manganese can be absorbed from the soil this causes disturbances in plant mechanisms. For instance disturbance of the division of water to hydrogen and oxygen, in which manganese plays an important part.

    Manganese can cause both toxicity and deficiency symptoms in plants. When the pH of the soil is low manganese deficiencies are more common.

    Highly toxic concentrations of manganese in soils can cause swelling of cell walls, withering of leafs and brown spots on leaves. Deficiencies can also cause these effects. Between toxic concentrations and concentrations that cause deficiencies a small area of concentrations for optimal plant growth can be detected.

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  4. [4]
    alshangiti
    alshangiti غير متواجد حالياً

    مشرف وإستشاري هندسة المناجم


    الصورة الرمزية alshangiti


    تاريخ التسجيل: Mar 2007
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    FOR EVERY THING ABOUT MINING

    http://www.infomine.com/minesite/minesiteall.asp

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  5. [5]
    alshangiti
    alshangiti غير متواجد حالياً

    مشرف وإستشاري هندسة المناجم


    الصورة الرمزية alshangiti


    تاريخ التسجيل: Mar 2007
    المشاركات: 1,472

    وسام مشرف متميز

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    كل ما تريد معرفتة عن التفجير فى الناجم

    http://www.mininglife.com/Miner/blasting/index.htm

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  6. [6]
    أبو حمزة السلفي
    أبو حمزة السلفي غير متواجد حالياً
    مشرف متميز
    الصورة الرمزية أبو حمزة السلفي


    تاريخ التسجيل: Dec 2007
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    المنجنيز

    بسم الله والحمد لله والصلاة والسلام على رسول الله

    هذه مشاركة متواضعة مني بعد ما أفاض أستاذنا الشنقيطي الموضوع بما لديه من معلومات

    http://www.wikifortio.com/484018/2.10.14 Manganese.pdf

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